The present invention relates to hydrofluoric acid-resistant ceramic mortars, and in particular to ceramic mortars in which the binding phase contains a metal salt having a particle size distribution imparting plasticity to the mortar that is either hydrofluoric acid-insoluble or is capable of forming a hydrofluoric acid-insoluble fluoride salt upon reaction with a fluorinating reagent. The present invention also relates to methods for forming hydrofluoric acid-resistant ceramic mortars in situ from mortars containing metal salt binding phases that are capable of forming hydrofluoric acid-insoluble fluoride salts upon reaction with fluorinating reagents. The present invention further relates to methods for bonding refractory brick into a brickwork unit using the hydrofluoric acid-resistant mortars of the present invention.
Generally, ceramic mortars contain silicate compounds that can be attacked by hydrofluoric acid (HF). For this reason, it is impossible to use silicate mortars for constructing HF reactors. At lower temperatures, stainless steel or carbon steel reactors with HF-resistant polymer coatings are used. However, at higher temperatures, reactors made of bricks such as carbon-bearing refractory bricks are used. Neither HF-resistant glasses or polymers can be used as a reactor liner because the softening temperatures of these materials are too low, generally between 300.degree. C. and 400.degree. C. Such lining materials may creep, and gases inside the reactor may then permeate through the reactor wall.
A need exists for ceramic mortars that do not contain silicate compounds, but exhibit HF resistance at elevated temperatures.